Thanks for the help, I actually have the second one with the silver top. Everything I have read about the mds 40 says the same thing you guys are saying about its quality. It is used engine that I got from a friend. He is big into planes himself. He tested and tuned it before he sent it to me, so hopefully everything works good. The only problem still is finding the cheap 15 dollar muffler that it originally came with. I went to the link of the pitts muffler but I don't think I want to spend that kind of dough on a motor that may not last that long. My sister's boyfriend's uncle recently died and he had several planes. They are sending all four planes with complete engines to me in a week or so. I hope the engines on those are useable and not mds. I probably wont buy an mds engine again.